1. Field of the Invention
The present invention relates generally to medical apparatus, systems, methods, and kits. More particularly, the present invention relates to methods and apparatus for isolating lobar and sub-lobar segments of the lung and delivering or retrieving substances from such isolated regions.
Lung access and isolation are of interest in numerous therapeutic and diagnostic medical procedures. In particular, access to the lungs is useful for both local and systemic drug delivery, lung lavage, visual assessment and diagnosis of lung function, lung volume reduction, and the like.
For drug delivery, access is most simply achieved by introducing an aerosol to the lungs through the mouth or nose, and a variety of inhalers, nebulizers, metered dose inhalers (MDIs), nasal sprayers, and the like, have been developed over the years. While very effective for many drugs, delivery through the mouth or nose can be very inefficient, often with less than 20% of the drugs reaching circulation or a targeted local treatment region. Moreover, inhalation through the mouth or nose is not able to target drug delivery to a particular region of the lungs. While this may not be a problem for systemic delivery, it can be a significant drawback in the treatment of localized disease where a highly controlled delivery profile would be preferred.
Of more particular interest to the present invention, techniques are presently being developed and implemented for intrabronchial volume reduction (xe2x80x9cIBVRxe2x80x9d) of the lung. Such techniques are described in detail in co-pending application Ser. Nos. 09/347,032; 09/523,061; and 09/606,320. Briefly, IBVR involves introducing a catheter to a lung passageway which feeds a diseased region of the lung. A cuff or other occlusion member on the catheter is then inflated in the lung passageway, and a plug or other obstruction formed in the passageway to occlude the diseased region of the lung. Optionally, the diseased region of the lung may be aspirated and/or drugs or other active substances delivered to that region in order to effect treatment. The IBVR techniques are intended as non-surgical alternatives to lung volume reduction surgery.
Heretofore, it has been proposed to perform both IBVR and lung lavage protocols using an integrated catheter which can be introduced to the lung through the conventional or thin-walled endotracheal tube. In some instances, the procedures are performed without any endotracheal tube with the patient under local anesthesia. The endotracheal tube is positioned in the trachea, and the integrated catheter passed distally through the endotracheal tube and guided to a target site in a lung passageway which feeds the diseased region of the lung. In order to achieve both proper positioning and lung occlusion, the integrated catheter will comprise at least the following components: (1) a viewing scope including both viewing and illumination fibers, (2) a cuff or balloon structure for occlusion of the lung passageway, and (3) a lumen or working channel for delivery of the lung occlusion plug, device, glue, or the like.
Because of the multiple functions required of the integrated catheter, the cost can be significant. In addition to cost, the medical facility where the procedure is to be performed must maintain an inventory of the integrated catheters, which inventory is in addition to all the other lung access, treatment, diagnosis, and other devices which may be routinely maintained by that facility.
One other device which is commonly maintained by medical facilities to perform procedures on the lungs is a xe2x80x9cbronchoscope.xe2x80x9d The bronchoscope is a type of endoscope which is specially adapted to be introduced through an endotracheal tube or directly into a lung passageway to permit viewing of the interior of the lung. The bronchoscope will typically comprise a flexible elongated body, and optical viewing fiber or a video chip, and a light transmitting bundle. The scope may be connected to a conventional viewing system which permits real time viewing of that portion of the lung which has been accessed by the bronchoscope. Optionally, the bronchoscope may include a working channel or lumen to permit conventional procedures, such as biopsy, lavage, retrieval of foreign matter, stent placement, laser therapy, or the like. While the bronchoscopes will typically be formed from a polymeric tube or shaft, it may also be formed from articulated structures which permit introduction through the tortuous regions of the lung. In either case, the bronchoscope will typically not be provided with an occlusion cuff or balloon to permit temporary occlusion of a lung passageway to isolate a region of the lung.
For these reasons, it would be desirable to provide improved apparatus, systems, methods, and kits for accessing and occluding a patient""s lungs, particularly a lobar or targeted sub-lobar region of the patient""s lungs. The present invention should particularly provide for a modification of a conventional bronchoscope or other lung viewing scope so that the scope can be used in procedures which require selective lung isolation. The modified viewing scopes should be useful for performing a variety of procedures which require both access and selective occlusion, including IBVR, segmental ventilation diagnostics, lung lavage, lung drug delivery, and the like. At least some of these objectives will be met by the invention described hereinafter.
2. Description of the Background Art
U.S. Pat. No. 5,607,386, illustrates a bronchoscope positioned in the lumen of a malleable xe2x80x9cstyletxe2x80x9d which, in turn, is positioned in a standard endotracheal tube which is cut to 25 cm or less. An endotracheal tube with integral optical viewing and illumination fibers is illustrated in U.S. Pat. No. 5,285,778. A device for treating blebs in lungs and including an elongate member having a balloon and imaging illumination fibers is illustrated in WO099/01076. Other bronchial catheters and treatment systems are described in U.S. Pat. Nos. 5,954,636; 5,904,648; 5,660,175; 5,645,519; 5,400,771; 4,976,710; 4,961,738; 4,886,496; 4,862,874; 4,846,153; 4,819,664; 4,784,133; 4,716,896; 4,453,545; 4,327,720; 4,086,919; 4,041,936; 3,913,568; 3,866,599; and 3,162,190.
The subject matter of the present application is related to that of the following commonly assigned, co-pending applications: U.S. Ser. Nos. 09/606,320; 09/523,016; 09/425,272; and 09/347,032, the full disclosures of which are incorporated herein by reference.
The present invention provides improved apparatus, systems, methods, and kits for accessing and occluding lung passageways, particularly passageways leading to lobar and sub-lobar regions of a patient""s lungs.
The isolated region will be a portion (usually not the whole) of the right or left lung, and isolation will be accomplished by occluding a bronchial passage at least one location in the lobar, segmental, and subsegmental bronchus. Thus, a primary occlusion will be formed after both the main bifurcation of the trachea and a further bifurcation into the lobar bronchus. Optionally, the lobar and/or sub-lobar region can be further isolated at at least one secondary location distal to the primary point of isolation and usually after further branching of the bronchial passages. Isolation at the primary location and optional additional locations within the bronchial passages will usually be effected by expansion of an occlusion member, such as an inflatable cuff, inflatable balloon, or the like.
Once the lobar or sub-lobar region has been isolated, a variety of therapeutic and diagnostic procedures can be performed within the isolated region. A presently preferred therapeutic procedure which can be performed using the systems and methods of the present invention is referred to as xe2x80x9cintrabronchial volume reductionxe2x80x9d (IBVR). IBVR is a non-surgical technique for isolating and occluding diseased lobar and sub-lobar regions of a patient""s lung. A systems and methods of the present invention will provide for access and temporary occlusion of these regions, and the regions may thereafter be permanently occluded and optionally aspirated in order to complete the therapeutic protocol. Such methods are described in detail in co-pending applications Ser. Nos. 09/606,320; 09/523,016; and 09/347,032.
In addition to IBVR therapy, the methods and systems of the present invention are useful for lavage and drug delivery. For example, pharmaceutical formulations including small molecule drugs, biological macromolecular drugs, and the like, can be specifically delivered to the isolated region with minimal or no cross-delivery to other regions of the lungs. Similarly, lavage may be performed within the isolated region with minimal impact on adjacent regions of the lungs. Isolation of the lobar or sub-lobar region permits such drug delivery and lavage procedures to be further controlled by control of the volumes, rates, pressures, temperatures, repetitions, retention times, and other method and system parameters. For example, the pressure within the isolated region can be controlled separately from the pressure or pressures maintained outside of the isolated region. In this way, a variety of delivery parameters can be controlled. By elevating pressure within the isolated region above that in the surrounding regions of the lung, the isolated lobar or sub-lobar region will be expanded which may, in some cases, enhance delivery of a drug or permit more efficient lavage of the region. Alternatively, by elevating pressure within the xe2x80x9cotherxe2x80x9d lung regions above that within the isolated region, the risk of migration of toxic therapeutic or other agents away from the isolated region can be greatly reduced.
In a first particular aspect, the present invention comprises a method for accessing and occluding a lung passageway. The method comprises providing a viewing scope which includes or consists essentially of a flexible elongated body, an optical viewing fiber or video chip, and a light transmitting bundle. The viewing scope may be in the form of conventional bronchoscope or a conventional articulated flexible scope having dimensions suitable for introduction in and through lung passageways to reach the lobar and sub-lobar regions of a patient""s lungs. Optionally, the bronchoscope or other viewing scope may include a working channel to permit infusion, aspiration, and/or introduction of other materials, such as adhesives, plugs, and the like, for occluding the lung passageway. Alternatively, a lung occlusion can be achieved through other means. Suitable viewing scopes will have the dimensions set forth in Table II below.
A sheath intended for use with the viewing scope will also be provided. A sheath comprises a flexible tubular body having a proximal end, a distal end, and at least a first lumen therethrough. The sheath will further comprise an inflatable cuff disposed near its distal end, where the inflatable cuff may be inflated through a lumen which is present in the tubular body itself or formed in a separate inflation tube. The viewing scope is introduced into the lumen of the flexible tubular body of the sheath to form an assembly where a viewing end of the viewing scope is located at the distal end of the sheath. The assembly of the viewing scope and sheath may then be introduced to a lung passageway so that the inflatable cuff lies adjacent to a target location in the passageway. The cuff may then be inflated to temporarily occlude the target location.
After such temporary occlusion is achieved, a variety of specific therapeutic, diagnostic, and other procedures may be performed in a region of the lung distal to the temporary occlusion. Of particular interest to the present invention, a plug element may be introduced to the target location in order to permanently occlude the passageway and isolate a lobar or sub-lobar region of the lung. Typically, such introducing comprises advancing the plug element through a lumen of the viewing scope to the target location. Alternatively, introducing may comprise withdrawing the viewing scope from the sheath and advancing the plug element through the lumen of the sheath. Still further alternatively, introducing may comprise advancing the plug element through a second lumen of the sheath while the viewing scope remains in place in the first lumen of the sheath. Of course, more than one introducing step may be employed using any one, two, or three of the alternative introducing techniques just described. In some instances, different plug elements, or different components of a plug element assembly, could be introduced through different lumens, and/or at different times in order to effect the desired occlusion of the lung passageway. Particular plug elements and structures are described in co-pending application Ser. No. 09/699,302, the full disclosure of which is incorporated herein by reference. Similarly, various obstruction devices could be introduced in the same or similar manner to the plug elements. A full description of such devices is provided in co-pending application Ser. No. 09/699,302, assigned to the assignee of the present invention. The present invention will embrace all of these particular approaches.
In a preferred aspect of the method of the present invention, the sheath and the viewing scope may be locked together prior to introducing the assembly to the lung passageway. Such locking may be achieved in a variety of ways, but will usually be accomplished using a Luer or other pneumostatic fitting disposed at the proximal end of the sheath. The fitting may be opened to permit introduction and free axial movement of the viewing scope through the lumen of the sheath. After the viewing end of the viewing scope has been properly aligned with the distal end of the sheath, typically with the distal tip of the viewing scope being located within 1 or 2 mm of the distal opening of the first lumen of the sheath, the fitting may be locked on to the viewing scope.
In a further preferred aspect of the present invention, the viewing scope will be aligned within the sheath by advancing the viewing scope until a distal end of the scope engages a stop element at the distal end of the sheath. The stop element will prevent further distal advancement of the viewing scope and position the viewing end of the viewing scope at the optimal location within the sheath.
In a still further specific aspect of the methods of the present invention, a pressure transducer, such as a solid state pressure transducer bridge or other integrated pressure measurement device, located at or near the distal end of the sheath. A signal representative of the pressure at the distal end of the sheath may be taken out through the sheath using wires, coaxial cable, or other suitable electronic-connecting components. Pressure measurement using a transducer located at the distal end of the sheath is advantageous since it provides a direct measurement in real time. The use of isolated pressure measurement lumens, where the pressure measurement device is located external to the patient, is generally less accurate and suffers from a time delay and signal damping.
The present invention further provides sheaths for use in combination with a viewing scope. The sheath comprises a flexible tubular body having a proximal end, a distal end, and at least a first lumen therethrough. An inflatable cuff is disposed at or near the distal end of the flexible tubular body, and the sheath will have the dimensions set forth in Table I below.
In a preferred embodiment, the sheath will further comprise a stop element disposed near the distal end of the tubular body to axially limit the travel of the viewing scope in the first lumen. Typically, the stop element will comprise a barrier which mechanically engages a portion of the viewing scope to prevent further travel by the viewing scope in the distal direction. The stop element may comprise a ring, flange, tube eversion, or the like, and will typically be disposed at the distal tip of the sheath and extend radially inwardly across an outer portion of the first lumen to provide the desired barrier. A wide variety of specific configurations are available. The particular dimensions in geometry of the stop element, however, should be selected so that they will not significantly interfere with either the viewing bundle or illumination bundle provided in the viewing scope.
In a further preferred aspect of the sheath, a distal end of the inflatable cuff will be disposed on the tubular body of the sheath at a distance from the distal end of the tubular body in the range from 0 to 2 cm, preferably 0 to 1 cm, and typically 0.05 mm to 2 cm.
In a further preferred embodiment, the inflatable cuff will be elastic and conform closely to an exterior surface of the tubular body of the sheath when not inflated. The cuff may have a variety of conventional or less conventional geometries, including spherical, cylindrical, disc-like, double disc-like, and the like. The inflatable cuff length will usually be in the ranges set forth above. In a specific aspect of the present invention, the inflatable cuff will be formed as an eversion of the distal end of the tubular body. The everted end of the tubular body will usually be comprised of the same material as the proximal length of the tubular body, optionally being thinned. Alternatively, the distal end of the tubular body can be composed of a different material having different mechanical and/or chemical properties. For example, the proximal portion of the tubular body may be formed from a relatively rigid and/or thicker material, while the distal portion which is everted into the cuff may be formed from a thinner and/or more elastic material.
In other aspects of the sheath, the first lumen may be coated with a lubricious coating, such as hydrophilic polymers (PVP, DMAA, TEGDMA, PVA, PEO, PNVP, etc.), carboxylic acids, cellulose ethers, collagens, and the like. Alternatively, or additionally, the first lumen may be textured to reduce friction, where texturing can include the formation of protrusions along the interior surface, rifling, or other known friction-reducing methods.
The sheath may further comprise a proximal fitting which can be selectively sealed over the viewing scope when the viewing scope is present in the lumen of the tubular body. An inflation lumen of the sheath may be brought out through the fitting or formed in a separate tube which detaches from the tubular body at a point distally of the fitting. The sheath may further comprise a pressure measurement transducer as generally described above in connection with the method.
The present invention still further comprises methods for making a sheath for use in combination with a viewing scope. The methods begin with an unexpanded polymeric tube, typically composed of a nylon (polyamide polymer), a high density polyethylene (HDPE), low density polyethylene (LDPE), a polyurethane, a silicone polymer, a polyester, a polyimide, or the like. The tube may be formed from the same material over its entire length, or optionally a distal portion of the tube (which eventually becomes the inflatable cuff) may be formed from a different material. Preferred cuff materials include silicone polymers, polyethylenes, polyurethanes, flexible vinyl butyrates, polyvinylchloride (PVC), polyvinylidene fluorides, polyolifins, polyesters, polyether/amide block co-polymers, and the like. A ring or other peripheral constraining element is placed over the unexpanded polymeric tube at a preselected distance from a distal end of the tube. The polymeric tube is expanded in a mold which defines an inflation cuff in a portion of the tube distal to the ring, and the ring creates a narrow width location in the expanded tube. The inflation cuff, i.e., portion of the tube distal to the ring, is then everted proximally over the tube, where the ring then defines a distal tip of the everted tube. A proximal portion of the cuff is then sealed to the exterior of the tube (that portion of the tube which then forms the shaft of the sheath) in order to create the inflation cuff. An inflation lumen will be formed in or on the resulting sheath construction. Usually, the unexpanded tube will have at least a second inflation lumen formed in a wall thereof, and the inflation lumen can be opened into the interior of the cuff which is later formed by eversion. Alternatively, a separate inflation tube can be attached to the interior or exterior of the sheath shaft to provide for inflation of the cuff.
The present invention still further provides kits for assembling and using a sheath and viewing scope assembly. The kits comprise a sheath having an inflatable cuff near a distal end thereof and instructions for use setting forth a method for introducing a viewing scope into a lumen of the sheath. The instructions may set forth any of the specific and preferred aspects of the methods of the present invention as described above. Kits will typically further comprise a suitable package for holding the sheath together with the instructions for use. Such packages may comprise any conventional medical device package including boxes, trays, tubes, pouches, or the like. Usually, the sheath will be maintained within the package in a sterile condition.
In all previously described aspects of the present invention, the sheath or sheath structure may optionally be provided with one or more additional inflatable cuffs to facilitate xe2x80x9cone lung ventilation.xe2x80x9d By xe2x80x9cone lung ventilation,xe2x80x9d it is meant that the lung in which the intervention is occurring will be isolated from the other lung, and the other lung will be ventilated. The additional inflatable cuff(s) on the sheath will be used to achieve the lung isolation. Of course, the additional cuff(s) could also be used to isolate lobar or sub-lobar lung segments for other purposes as well.
In a first exemplary embodiment, a sheath will comprise a flexible tubular body having at least a first inflatable cuff disposed near a distal end thereof, generally as described above. A sleeve or equivalent slidable structure will be provided over the exterior of the flexible tubular body, and the sleeve will include at least a second inflatable cuff, usually near a distal end thereof. A second inflatable cuff may be positioned in a lung passageway just distal to the main bifurcation between the two lungs. The second cuff may then be inflated in order to isolate one lung from the other lung. The other lung can then continue to be ventilated, while the procedures of the present invention can be performed in the one lung using the flexible tubular body and first inflatable cuff, generally as described above.
In a second exemplary embodiment, a second and optionally third, fourth, and further additional inflatable cuffs will be disposed directly on the flexible tubular body of the sheath. The first inflatable cuff, which is disposed at or near the distal end of the flexible tubular body will still be positioned at the target lung passageway located within the target lung. One of the second, third, fourth, or further inflatable cuffs will then be selected to isolate the target lung. In particular, that additional inflatable cuff which lies nearest the main lung bifurcation (or other desired isolation point) will then be selectively inflated to provide the desired isolation. The main viewing, biopsy, or other desired procedure may then be performed using the bronchoscope which is introduced through the sheath lumen, generally as described above.